Disposable foam container for food products

ABSTRACT

A foam container with an upper portion and a lower portion is provided. Upper lips formed by edges of upper walls of the upper portion distal from the top of the upper portion extend outward from the upper walls, while lower lips formed by edges of lower walls of the lower portion distal from the bottom surface extend outward from the upper walls. A groove is defined by the upper lips, and a rim is disposed at least partially along the lower lips. A peripheral indented segment in the lower walls and a peripheral ridge formed by the upper walls are dimensioned so as to render the container securably stackable with other containers. Arcs may be formed on the lower walls and the upper walls. The arcs may be centered on the walls with the walls having a thicker cross-section within at least a portion of the arcs.

BACKGROUND OF THE INVENTION

In food service operations such as restaurants, diners, and fast food establishments, “to-go-boxes,” or take-out boxes, have become a standard device in which take out orders may be placed. These take-out boxes or containers are usually made of a top half and a bottom half. The food to be delivered or picked up by the customer is placed in the bottom half of the box either on a disposable plate or on the bottom of the box itself. Then, the top half of the box is closed to cover the bottom half. Through the use of such boxes or containers, the delivery of prepared food is made more convenient. Also, the convenience of picking up food, instead of cooking in, still affords people the option of eating at home. As portions of meals have become larger, these containers easily allow customers at restaurants to take their leftover food home without the use of a messy “doggy bag.”

Some take-out boxes have been made out of cardboard. While this allows the user to carry his food home, these boxes are not ideal for holding food items. The cardboard take-out boxes are prone to leaking and absorbing moisture, are flimsy, and do not retain heat well. Further, the cardboard take-out boxes require an assembly step.

More advanced containers have been developed that are made from a foam material. These conventional containers are more convenient in that they do not have to be assembled like cardboard boxes, and they can be made out of a single unitary construction. The top half of the container can be connected to the bottom half of the container by a hinge portion between the two halves. This allows the containers to be stacked in an open position for shipping and they can be pulled out directly for use. Generally, foam containers are sturdier than the cardboard boxes. Also, they insulate the food better and do not absorb moisture from the food.

Due to their unitary construction, the food placed in conventional foam containers does not leak through the foam. Such foam containers eliminate the need for the use of a disposable plate when hot food is placed in the containers. These foam containers come in many different shapes from small sandwich boxes for holding a single sandwich, to larger containers with a flat bottom, to containers which are compartmentalized to allow different types of food to be placed in different compartments. These conventional foam containers are made into their predetermined constructed shape by having the foam injected into molds or stamped out into its final form.

However, these conventional foam containers still have problems due to their design. Generally, the top half of the container folds onto the bottom half of the container, where the top half is somehow attached to the bottom half of the container at an end distal from the hinge. The edges around the bottom half of the conventional foam container generally meet the edges around the top half of the foam container. In some designs, the top half actually overhangs the bottom half. By only having the edges of the bottom half and the top half of the conventional container meeting when the container is in this closed position or by having the upper half overhanging the bottom half of the container when it is in its closed position, the two halves of the containers still easily separate.

The separation of the top half and the bottom half of the conventional foam containers lead to many of the same problems experienced by take-out cardboard boxes. Due to the separation along the edges of the two halves of conventional foam containers, the food within the containers easily leaks from the sides of the containers. In this manner, if a conventional foam container is accidentally tipped to one side, food within the container would spill from between the two halves of the container. Further, the separation between the two halves of a container may allow excessive amounts of heat to escape when hot food items are placed in the container.

Another issue that arises with the conventional foam container relates to stacking. Often, conventional foam containers are stacked on top of one another when they are in their closed positions. Some restaurant owners prep the containers by placing certain items, such as cutlery kits, napkins, or wax paper in the containers and closing them in preparation for receiving food. These prepped containers are then stacked on top of one another. However, because conventional foam containers usually have a slick surface, it is hard to stack these containers onto one another.

Further, when food items are being delivered, the delivery person often stacks multiple closed containers on top of one another. A greater problem arises if conventional foam containers holding food are stacked. In containers in which the upper half overhangs the lower half or in containers where the edges of the upper half meet the edges of the bottom half, the weight of the filled containers often causes the upper half of the container on the bottom of the stack to collapse. Further, the walls on these containers can often bend easily and generally do not withstand more than minimal amount of weight placed upon them. Therefore, the convenience of delivering multiple meals in such conventional containers can be limited due to their inability to be stacked in a convenient and securable manner.

Thus, a need currently exists for a disposable food container which is rigid and sturdy, does not leak, and insulates the food while not absorbing the moisture from the food items placed therein. Additionally, a need exists for a foam container which is securably stackable that has walls that can withstand a certain load.

SUMMARY OF THE INVENTION

In an exemplary embodiment, a foam container has an upper portion forming a top of the container and a lower portion forming the base of the container. The upper portion has a top surface and defines upper walls that extend from the top surface. The lower portion has a bottom surface and defines lower walls extending from the bottom surface. A hinge is disposed between one of the lower walls and one of the upper walls. The hinge connects the upper portion and lower portion together to permit the upper portion and lower portion to open and close.

Upper lips distal from the top surface extend outward from the upper walls. Similarly, lower lips distal from the lower surface extend outward from the lower walls. A groove is defined in the upper lips, while a rim is disposed at least partially along the lower lips with the rim extending above the lower lips. The rim engages the groove when the container is in a closed position.

A latching system may be disposed in the upper portion and lower portion of the container. The upper portion and the lower portion may be securable together by the latch system so that the upper lips reside proximal to the lower lips and the groove, is disposable around the rim when the upper portion and the lower portion are in a closed position.

The upper walls and the lower walls may form different shaped containers such as circular containers, rectangular containers, and triangular containers. In such embodiments the upper walls are integral together as they extend from the tops surface, while the lower walls are integral together as they extend from the bottom surface of the container. The upper walls may extend from the top surface and the lower walls may extend from the bottom surface at different angles. Preferably, the angles at which the upper walls and the lower walls extend from the top surface and bottom surface respectively are between about 90° and 150°. In some exemplary embodiments, arcs may be formed on the upper walls and lower walls. These arcs are centered on each of the upper and lower walls with the walls having a larger cross-section within at least a portion of the arcs.

The groove defined by the upper lips may fit onto the rim at least partially formed by the lower lips in such a manner that the upper walls extend below the rim when the container is in a close position. In some embodiments, the rim may be formed by both the lower walls and lower lips. In such embodiments, the rim may be an extension of the lower walls.

The hinge of the containers which is disposed between the upper portion and lower portion of the container works together with the latch system to hold the containers in a close position. The hinge may be disposed between one of the upper lips formed by the upper walls and one of the lower lips formed by the lower walls. The latch system may be disposed on one of the upper walls and one of the lower walls distal from the hinge.

Different latch systems may be employed. One latch system may have a latch extending from one of the upper walls distal from the hinge and a slot defined in one of the lower walls distal from the hinge, whereby the latch is slideable into the slot to close the container.

To allow the containers to be securely stackable, the lower walls may have a peripheral indented segment therein proximal to the bottom surface of the container while the upper walls may form a peripheral ridge that extends above and around the top surface of the container. In this manner, the indented segment around the bottom of the containers and the peripheral ridge around the top of the containers allow the containers to be stackable one on top of the other. The peripheral indented segments of the lower walls of the lower portion and peripheral ridge formed in the upper walls of the upper portions of the containers are dimensioned so as to render the containers stackable with other similarly constructed containers. Such dimensions allow a bottom surface of a first container to rest upon a top surface of a second container, whereby a peripheral indented segment of lower walls of the first container fits within a peripheral ridge formed by upper walls in the second container. In this manner, multiple containers may be stacked one upon the other in a securable fashion.

In similar embodiments of the foam container, an upper portion forming the top of the container and the lower portion forming the bottom of the container may be provided. The upper portion has a top surface with upper walls extending from the top surface, while the lower portion will have a bottom surface with lower walls extending from the bottom surface. As described above, a peripheral indented segment formed within the lower walls proximal to the bottom surface while a peripheral ridge formed in the upper walls extends above and around the top surface of the container. In such embodiments, the peripheral indented segments in the lower wall and the peripheral ridge formed in the upper walls are dimensioned as to render the container securely stackable with other containers.

In a further embodiment, the upper portion which forms the top of the container has a top surface with upper walls extending therefrom. A lower portion that forms the base of the container has a bottom surface with lower walls extending therefrom. Arcs are formed on the lower walls and the upper walls to increase the rigidity of the walls. The walls will have a thicker cross-section within at least a portion of the arcs. The arcs may be centered on each of the walls so that an apex of each arc is proximal to the center of a length of the wall on which the arc is formed.

All the features of the subject matter will be described in greater detail through the use of the appended figures.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present invention, including the best mode thereof, to one of ordinary skill in the art is set forth more particularly in the remainder of the specification, including reference to the accompanying figures, in which:

FIG. 1 is a perspective view of an embodiment of a closed disposable container of the present invention;

FIG. 2 is a top view of the disposable container shown in FIG. 1;

FIG. 2A is a cross-sectional view taken along the lines 2A showing a groove in an upper portion of the disposable container of FIG. 2;

FIG. 2B is a cross-sectional perspective view taken along the line 2B along a lower portion of the disposable container of FIG. 2;

FIG. 3 is a perspective view from the bottom of the disposable container of FIG. 1;

FIG. 4 is a cross-sectional view of two stacked disposable containers according to one embodiment of the present invention; and

FIG. 5 is a close-up view of a segment of the lower portion of the bottom container shown in FIG. 4.

DETAILED DESCRIPTION

Reference will now be made in detail to the presently preferred embodiment of the invention one or more examples of which are shown in the figures. Each example is provided to explain the invention and not as a limitation of the invention. In fact, features illustrated or described as part of one embodiment can be used with another embodiment to yield still a further embodiment. It is intended that the present invention cover such modifications and variations.

The present invention is generally directed to a disposable food container for food products. These containers can take on many forms from small sandwich containers to large containers to compartmentalized containers. Further, the containers are not necessarily limited to any one shape. More specifically, the disposable container of the present invention contains structural formations which can not only increase the rigidity and strength of the container, but also can make the container more efficient to use. For example, the container of the present invention can be formed such that an upper portion of the container can be closed on a lower portion of the container in a manner that the food items placed within the container are better sealed and insulated within the container.

The container of the present invention is generally formed of a single piece of a material which is shaped to form the container. This material is molded into the shape of the container. While the material of formation is not critical to the present invention, various parameters of the containers such as, for example, strength and ductility can be further improved through choice of material.

In an exemplary embodiment, the container may be formed of a material which can not only provide additional strength and ductility to the container, but is also environmentally friendly. For example, the containers can be formed of a material which is completely recyclable and contains no environmentally hazardous chemicals, such as chlorofluorocarbons (CFC's or HCFC's). Some materials useful for construction include microcellular foamed materials, such as microcellular foamed polystyrene materials available from the Trexel Corporation of Woburn Mass.

Microcellular foamed materials include those which in general possess homogeneous microcellular cell sizes of less than about 50 microns and cell densities lying in a range of from about 10⁹ to 10¹⁵ per cubic centimeter of material. Rather than being formed by use of hydrocarbon introduction into a plastic, as is the case with more traditional types of foamed products, microcellular foamed polymer materials can be formed with carbon dioxide introduced into the plastic to form voids. The use of CO₂ can help prevent the presence of any potentially hazardous chemicals in the container material.

The microcellular foamed polymers which can be used in the present invention include foamed polystyrene products. These preferred materials are generally both stronger and lighter weight than foamed products produced by other methods. Microcellular foamed products can display greater ductility than other foamed products, allowing the product to bend farther without failure than do foamed products formed by other methods.

When prepared from these materials, the containers of the present invention can have a smooth, leak proof finish. The processes used to produce microcellular foam products can be controlled to produce a product having a thin skin without voids. This thin skin on the surface of the product not only improves surface impact strength, but also allows finishing operations which can provide a smooth finish which not only proves attractive, but prevents food absorption and leakage through the container.

Details of the processes involved in producing various microcellular foams can be found in U.S. Pat. No. 4,473,665 to Martini-Vvedensky et al., U.S. Pat. No. 5,158,986 to Cha et al., U.S. Pat. No. 5,160,674 to Colton et al, and U.S. Pat. No. 5,334,356 to Baldwin et al., all of which are herein incorporated in their entirety by reference thereto.

Of course, the containers of the present invention may be formed of other materials as well, such as other foamed polymer products. When formed of a foamed product, whether a microcellular foamed polymer or a more conventional foamed product, the product material can be an extruded material, which is then thermoformed to produce the shape of the container.

Whatever material is chosen for the container, it is generally capable of adequately holding hot food without either allowing the food to leak through or otherwise causing damage to the container or the meal. For example, the material of the container should be able to withstand temperatures of up to about 200° F. without damage to the container. One of the advantages to using a foamed polymer material is the insulating properties of foam, which can allow a person to carry a container including hot food items without excessive heat reaching the hands.

Referring to FIGS. 1-3, for example, one embodiment of a foam container, generally 10, is illustrated that has an upper portion 12 and a lower portion 14. The upper portion 12 forms a top half of the container, while the lower portion 14 forms the bottom half, or the base, of the container. The upper portion 12 has a top surface 16 from which upper walls 18 extend. The lower portion 14 has a bottom surface 28 from which the lower walls 26 extend. The two portions 12, 14 of the container 10 are connected by a hinge 44 located between one of the lower walls 26 and the upper walls 18. The hinge 44 allows the upper portion 12 of the container 10 to fold onto the lower portion 14, thereby permitting the container 10 to close and open. The upper walls 18 of the upper portion 12 define upper lips 20 around its edges distal from the top surface 16. The upper lips 20 extend outward from the upper walls 18. Similarly, lower walls 26 define lower lips 24 around their edges distal from the bottom surface 28 of the lower portion 14. When the upper portion 12 is rotated about the hinge 44 and is thus closed on the lower portion 14 of the container 10, the upper lips 20 abut against the lower lips 24.

FIGS. 2A and 2B are perspective cut away views of the upper portion 12 and the lower portion 14, respectively. As shown in FIG. 2, for example, the upper lips 20 form a groove 32 between the end of the upper lips 20 and the upper walls 18. Inversely, a rim 34 is formed at least partially along the lower lips 24. The groove 32 has sufficient depth and curvature to accept the rim 34 of the lower portion 14. A curved end portion 19 of the wall 18 just outside of the groove 32 is tangentially parallel, or almost parallel, to a surface 21 of the lip 20 which faces toward the lower lip 24 when the foam container 10 is closed. As seen in FIG. 2B, the rim 34 extends above the lower lips 24 to a specified height. In an exemplary embodiment, when the top portion 12 is closed about the hinge 44 onto the lower portion 14, the groove 32 fits over the rim 34 so that the surface 21 of the upper lips 20 are in contact or at least in close proximity to a surface 25 of the lower lips 24 as can been seen in FIG. 1. The interaction of the groove 32 and the rim 34 results in better insulation of food placed in the container 10, and also results in the container 10 being less susceptible to leaking of fluids from the food items placed in the container 10.

A latch system 38 is disposed in the upper portion 12 and the lower portion 14 of the container 10. The upper portion 12 and the lower portion 14 are securable together by the latch system 38 so that the surface 21 of the upper lips 20 resides proximal to the surface 25 of the lower lips 24. Also, the groove 32 is disposable around the rim 34 when the upper portion 12 and the lower portion 14 are in a closed position. The latch system 38 holds the container 10 in its closed position.

In the exemplary embodiment, the latch system 38 includes a latch 40 which is extendable from the upper portion 12. The latch 40 is insertable into a slot 42 in the lower portion 14. The latch, or tab, 40 is easily insertable into the corresponding slot 42. Due to the construction of the foam container 10, the latch 40 may be inserted into the slot using a single hand by pushing against the upper wall 18 above the latch as it is being inserted into the slot 42. The pushing of the upper wall 18 above the latch 40 creates a spring like action which pushes the latch into the slot when a finger or hand is removed from the wall 18. The latch 40 may be designed so as not to protrude past the lower lip 20 when it is placed in the slot 42. A possible added benefit of the slot 42 is that it can serve as a vapor vent to allow steam from the food insert into the container to at least partially escape, thereby reducing condensation build up on the upper portion 12 of the container 10. At the same time, the slot 42 is not large enough to allow excessive amounts of heat to escape, thereby preventing the food within the container 10 from cooling too rapidly.

In the exemplary embodiment, the latch system 38 is placed on the upper wall 18 and the lower wall 26 that are distal to the upper wall 18 and the lower wall 26 between which the hinge 44 is placed. The rim 34 extends around the other walls 26 and at least partially extends above the lower wall 26 in which the slot 42 is formed. Similarly, the groove 32 extends around three of the upper walls 18 and at least partially extends around the upper wall 18 on which the latch 40 is formed. By having the rim 34 and the groove 32 extending around the lower walls 26 and the upper walls 18 in such a manner, the interaction of the groove 32 with the rim 34 help to keep food in the container 10 as well as to keep the heat from the food within the container 10 from escaping, while still permitting the latching system 38 to hold the container 10 in a closed position.

The latch system may take on other various forms including having the latch on the lower portion and a slot on an upper or may include some other known conventional system for closing foam food containers.

The hinge 44 may be a fold in the foam material used to construct the container. By having the hinge 44 placed between the upper portion 12 and the lower portion 14, the container 10 is made out of a unitary piece of foam. This hinge 44 may be a single fold or may contain other number of folds which may help to keep the upper portion 12 laying flat on the lower portion 14 when the container 10 is in a closed position.

For example, in an exemplary embodiment shown in FIG. 2, a W-shaped multiple groove hinge is employed. Hinge 44 has a first groove 46 and a second groove 48. The grooves 46, 48 allow the container 10 to close completely with little or no gap at the edges of the upper and lower portion, helping to minimize the spring like action of a single fold, which can push the upper and lower portions of a container apart. A middle portion 47 may be shaped in the form of a triangle to facilitate the folding and laying of the upper portion 12 on the lower portion 14 when the container 10 is closed. In the same manner, this hinge design with the first groove 46 and the second groove 48 also allows the container 10 to be fully open when not in a closed position. This allows a user to place food into a container 10 without having to hold the container 10 open.

The upper walls 18 of the upper portion 12 of the container 10 define a peripheral ridge 22 that extends above and around the top surface 16 of the upper portion 12. Further, a peripheral indented segment 30 is formed in the lower walls 26 of the lower portion 14 of the container 10 that is proximal to the bottom surface 28 of the lower portion 14. The peripheral indented segment 30 in the lower walls 26 and the peripheral ridge 22 formed by the upper walls 18 are dimensioned so as to render the container 10 stackable with other containers. The bottom surface 28 of the container 10 can rest upon the top surface 16 of another container, whereby the peripheral indented segment 30 of the lower walls 26 of the container 10 fits within a peripheral ridge 22 formed by the upper walls 26 of the other container.

To better explain the interaction of the peripheral ridge 22 and the indented segments 30 as well as other features discussed above, FIG. 4 provides a cross-sectional view of two stacked containers. As shown in FIG. 4, a first container 110 is placed upon a second container 210. Each of the two containers 110, 210 are in a closed position with the lower portion 114 of the first container 110 resting upon an upper portion 212 of the second container 210. The upper portion 212 of the second container 210 has a top surface 216 with upper walls 218 extending therefrom. The upper walls 218 form a peripheral ridge 222 which extends above and around the top surface 216 of the second container 210. The second container 210 also possesses a lower portion 214 which is operably attached to the upper portion 212 as described above. The lower portion 214 has a bottom surface 228 with lower walls 226 extending therefrom. A peripheral indented segment 230 is formed in the lower walls 226.

The lower portion 114 of the first container 110 has a bottom surface 128 with lower walls 126 extending therefrom. The walls 126 form a peripheral indented segment 130 proximal to the bottom surface 128 of the lower portion 114 of the first container 110. When the first container 110 is placed upon the second container 210, the bottom surface 128 of the first container 110 rests upon the top surface 216 of the second container 210. At the same time, the peripheral indented segment 130 around the lower walls 126 of the lower portion 114 of the first container 110 nest into the peripheral ridge 222 formed by the walls 218 around the top surface 216 of the upper portion 212 of the second container 210.

As with the second container 210, the first container 110 possesses a peripheral ridge 122 around its top surface 116 formed by upper walls 118 of the upper portion 112 of the container 110. Thereby, the next container may be placed upon the first container 110.

In this manner, multiple boxes may be stacked upon one another either before or after food or other items are placed within the containers. Due to the peripheral ridges 12, 112, 212, the containers 10, 110, 210 are prevented from sliding off of one another when they are stacked, thereby allowing for a securable stacking of the containers 10, 110, 210. This securable stackability of the containers allows for easier transport of multiple containers when items such as food have been place therein. The securable stackability may also permit an easier staging of the containers when some items, goods, or food have been placed in the containers, while other items, goods, or food are to be placed into the containers at a later time.

In the embodiment shown in FIG. 4, as well as the other exemplary embodiment shown in FIGS. 1-3, it can be seen that the upper walls 18, 118, 218 extend from the top surface 16, 116, 216 of the upper portion 12, 112, 212 at an angle. Similarly, the lower walls 26, 126, 226 also extend from the bottom surface 28, 128, 228 of the lower portion 14, 114, 214 at an angle. As can be seen in FIG. 4, upper walls 118, 218 extend downward at an angle α as measured from a top panel 117, 217, which forms the top surface 116, 216 of the upper portion 112, 212. Further, the walls 126, 226 extend upward at an angle β from the panel 127, 227 forming the bottom surface 128, 228 of the lower portions 114, 214.

The angles α and β and the lengths of the upper and lower walls help improve the sealing of the containers and the ability of the container 10 to help withstand a load. In forming the containers 110, 210, the lengths of the upper walls 118, 218 and the associated angle α between the upper walls 118, 218 and the panels 117, 217, which form the top surface 116, 216 as well as the lengths of the lower walls 126, 226 and the angle β between the lower walls 126, 226 and the panels 127, 227 forming the bottom surface 128, 228 should each have measurements which allow the containers 110, 210 to close in a manner that prevents food or other items which are stored in the containers from leaking or falling out. In embodiments in which a rim 134, 234 and a groove 132, 232 are employed, it may be advantageous to have such measurements work in association with each other so that the upper walls 118, 218 have curved end points 119, 219, which extend to the base of the rim 134, 234 when the containers 110, 210 are in a closed position and the grooves 132, 232 are engaging the rims 134, 234. In embodiments as shown in FIG. 4 where the lower walls 126, 226 extend upward to form one side of the rim 134, 234 so that the rim 134, 234 appears to be an extension of the lower walls 126, 226, it may be advantageous for the end points 119, 219 of the upper walls 118, 218 to extend below the highest point in which the lower walls 126, 226 extend upward when the container 110, 210 is closed. In both embodiments, better sealing of the container 110, 210 occurs as well as improved support for the upper portion 112, 212 to prevent its collapse and to increase and improve the sealing of the upper portion 112, 212 and the lower portion 114, 214.

For example, a force may be placed in a direction F₇ upon the container 210 such as the weight of a full container 110 placed upon the top surface 216 of the container 210, or a user pressing down or grasping the upper portion 212 and pushing against the lower portion 214. Due to the angle α as well as the placement of the end points 219 of the upper walls 218, the end points 219 of the upper walls 218 push in the directions F₈ and F₉ against the rim 234 and/or the lower walls 226. At the same time, the forces in the directions F₈ and F₉ push the groove 232 downward against the rim 234. Thereby, the upper walls 218 and the groove 232 are supported by the lower walls 226 and rim 234 when forces are exerted downward in the direction F₇on the upper portion 212, further helping to support the upper portion 212 and the container 10.

In this manner, due to the placement of the end points 219 of the upper walls 218 as well as the groove 232 of the upper portion 212 interacting with the rim 234 of the lower portion 214, the upper portion 212 may withstand greater weight being placed upon its top surface 216. At the same time, the sealing of the groove 232 against the rim 234 is improved. For such an interaction, the angles α and β should be such that, when a force is placed downward on the top surface 216, the upper walls 218 push against the lower walls 226, while groove 232 pushes against the rim 234. Angle α and angle β may generally be different angles. However, the angles α and β should generally be greater than 90 degrees and less than 150 degrees.

In a similar manner, the interactions of the upper walls 218 and the lower walls 226 as well as between the rim 234 and the groove 232 help to keep the container 210 sealed and in a closed position when forces in lateral directions F₅, F₆ are placed against the upper portion 212 or lower portion 214. For example, a force in the lateral direction F₅ acting on the upper portion 212 will cause the end points 219 of the upper walls 218 to push in a direction F₂ against the wall 226 on the side in which the force is acting, while the force in the direction F₅ causes the outside portion of groove 232 to push against outside portion of the rim 234 in the direction F₃ on the side of the container 210 away from the direction F₅. In this manner, the portion of the rim 234 and the groove 232 on the side away from the direction in which the force is acting pushes against each other on the outside of the rim 234 and the groove 232, thereby reducing the chance of a separation between the lower portion 214 and the upper portion 212 on that side. At the same time, the rim 234 and the groove 232 on the side in which the force in the direction F₅ is moving has the inner portion of the groove 232 pushing against the inner portion of the rim 234. Again, this pushing of the groove 232 outward against the rim 234 reduces the chances of the lower portion 214 separating from the upper portion 212.

Conversely, when a force is acting in the direction F₆ on the upper portion 212 of the container 210, the upper wall 218 and the inner portion of the groove 232 push against the lower wall 226 and the inner portion of the rim 234 in the direction F₁ on the side of the container 210 in which the force in the direction F₆ is moving. On the side of the container 210 away from the direction F₆ in which the force is moving, the outside portion of the groove 232 pushes against the outside portion of the rim 234 in the direction F₄. In this manner the upper walls 218, lower walls 226, the groove 232, and the rim 234 help to keep the container 210 in a closed position and reduce the chances of separation between the lower portion 214 and the upper portion 212. In the same manner as described above, the angles α between the panel 217 forming the top surface 216 and the upper walls 218 of the upper portion 212 as well as the angels β formed between the panel 227 forming the bottom surface 228 and the lower walls 226 of the lower portion 214 help to ensure that the chances of separation between the upper portion 212 and the lower portion 214 are greatly reduced.

A further feature of the embodiment shown in FIG. 1-3 are arcs 50 on each of the upper walls 18, 188, 218, and the lower walls 26, 126, 226. These arcs 50 are placed in each of the walls, 18, 118, 218, 26, 126, 226 during the molding process of the foam containers. The arcs 50 protrude outward from the container and extend from a point proximal to the upper lips 20, 120, 220 or lower lips 24, 124, 224. The arcs 50 arrive at an apex 51 and descend back toward the upper lips 20, 120, 220 or lower lips 24, 124, 224. FIG. 5 shows a magnified view of an arc 50 on a lower wall 226 of a container 210 in FIG. 4. As can be seen in FIG. 5, the arc 50 may include an exterior arc 53 and an interior arc 52. The interior arc 52 has a radius of curvature which is slightly less than the exterior arc 53. The interior arc 52 and the exterior arc 53 are more pronounced at the apex 51 of the arc 50 than at the ends of the arc 50. This design adds greater strength and rigidity to the walls. In particular, it adds greater strength at the apex of the walls below the panel 17, 117, 217 of the upper portion 12, 112, 212 and the panel 27, 127, 227 of the lower portion 14, 114, 214.

As can be seen from this embodiment, the interior arc 52 and exterior arc 53 of the arc 50 creates a section I in the wall 226 which has an increased width as compared to the section 226 a below the section I and the width of section 226 b above the section I. Within the section I, the width of the wall 226 varies in size with the maximum width W₁ being within the apex 51 of the arc 50. The maximum width W₁ is larger than the width W₂ of the section 226 a and is also larger than the width W₃ of the upper section 226 b of the wall 226. In some embodiments, this maximum width W₁ may be twice the width W₂ or W₃.

The arcs 50 may be of a consistent width along the wall 18, 118, 218, 26, 126, 226 or may taper as they approach the lips 20, 120, 220, 24, 124, 224 as discussed above. By having an increased width W₁ within a section of the wall in the shape of an arc 50, increased strength is added to the walls especially when a compression force is placed above the apex 51 of the arc 50. Due to the shape of the arc 50, the increased cross-section within the arc 50 better supports itself when a load is added above the apex 51. Through the use of the arc 50 formed by the exterior arc 53 and interior arc 52 which shape the arc 50 in a curved fashion, strength may be added to the walls 18, 118, 218, 26, 126, 226 without greatly increasing the amount of foam material used to create the containers.

In some embodiments, it may be beneficial to have arcs 50 that do not have interior arcs 52 but rather continues along the shape of the traditional wall. Even in such an embodiment, the amount of material used within the container is less than with other embodiments in which all the walls are increased uniformly in cross-sectional size.

Through the use of any one of these features described above the foam containers used in the food service industry have increased capabilities. By using the peripheral ridge on the upper portion of the container and the indented segment on the lower portion of the container, the containers are more securably stackable. By employing the rim and groove lips, respectively, the container top is better supported and the sealing of the food items within the container is also enhanced. Further, the employment of an arc on the walls of the upper and lowers portions having a thicker cross-section than the rest of the walls increases the strength and rigidity of the walls. These features may be used in combination or alone to enhance the ability of the container to serve its end user.

These and other modifications and variations to the present invention may be practiced by those of ordinary skill of the art without departing from the spirit and scope of the present invention, which is more particularly set forth in the appended claims. In addition, it should be understood that aspects of the various embodiments may be interchanged both in whole or in part. Furthermore, those of ordinary skill in the art will appreciate that the foregoing description is by way of example only and is not intended to limit the invention so further described in such appended claims. 

1. A foam container comprising: an upper portion forming a top of a container, said upper portion having a top surface and defining upper walls extending from said top surface; a lower portion forming a base of said container, said lower portion having a bottom surface and defining lower walls extending from said bottom surface; a hinge disposed between one of said lower walls and one of said upper walls, said hinge connecting said upper portion and said lower portion together; upper lips extending outward from said upper walls, said upper lips defining a groove therein; lower lips extending outward from said lower walls, wherein a rim extends above said lower lips; and wherein said upper portion and lower portion are capable of being placed in a closed position so that said upper lips reside proximal to said lower lips and said groove engages said rim.
 2. A container as in claim 1, wherein said upper walls comprise four integral walls extending from said top surface and said lower walls comprise four integral walls extending from said bottom surface.
 3. A container as in claim 2, wherein said hinge is disposed between one of said upper lips and one of said lower lips.
 4. A container as in claim 1, wherein said upper walls extend from said top surface at an angle between about 90° and about 150°.
 5. A container as in claim 1, wherein said lower walls extend from said bottom surface at an angle between about 90° and about 150°.
 6. A container as in claim 1, wherein said groove fits over said rim in such a manner that said upper walls extend below said rim when said upper portion and said lower portion are placed in said closed position.
 7. A container as in claim 1, wherein said rim is formed by at least a portion of said lower walls and at least a portion of said lower lips.
 8. A container as in claim 7, wherein said rim is an extension of said portion of said lower walls.
 9. A container as in claim 1, further comprising a latch system wherein said upper portion and lower portion are securable together by said latch system when said upper portion and said lower portion are in said closed position.
 10. A container as in claim 9, wherein said latch system is disposed on one of said upper walls and one of said lower walls distal from said hinge.
 11. A container as in claim 9, wherein said latch system comprises a latch extending from one of said upper walls distal from said hinge and a slot defined in one of said lower walls distal from said hinge, whereby said latch is slidable into said slot to close the container.
 12. A container as in claim 1, wherein said lower walls form a peripheral indented segment therein proximal to said bottom surface.
 13. A container as in claim 12, wherein said upper walls form a peripheral ridge that extends above and around said top surface.
 14. A container as in claim 13, wherein said peripheral indented segment and said peripheral ridge are dimensioned so as to render the container stackable with another container of the same construction.
 15. A container as in claim 1, further comprising arcs formed by said lower walls and said upper walls, said arcs centered on each of said upper and lower walls and said upper and lower walls having a thicker cross-section within at least a portion of said arcs.
 16. A foam container comprising: an upper portion forming a top of a container, said upper portion having a top surface and defining upper walls extending from said top surface; a lower portion forming a base of said container, said lower portion having a bottom surface and defining lower walls extending from said bottom surface; a peripheral indented segment formed within said lower walls, said peripheral indented segment being proximal to said bottom surface; a peripheral ridge formed by said upper walls, said peripheral ridge extending above and around said top surface; said peripheral indented segment in said lower walls and said peripheral ridge formed by said upper walls being dimensioned so as to render the container securably stackable with another container of the same construction.
 17. A container as in claim 16, further comprising a hinge disposed between one of said lower walls and one of said upper walls, said hinge connecting said upper portion and said lower portion together so that said upper portion and lower portion are capable of being placed in a closed position.
 18. A container as in claim 17, further comprising a latch system wherein said upper portion and lower portion are securable together by said latch system.
 19. A container as in claim 18, wherein said latch system is disposed on a side of said upper portion and a side of said lower portion distal to said hinge.
 20. A container as in claim 19, wherein said latch system comprises a latch extending from said upper wall distal from said hinge and a slot defined in said lower wall distal from said hinge, whereby said latch is slidable into said slot to close the container.
 21. A container as in claim 17, further comprising upper lips extending outward from said upper walls and lower lips extending outward from said lower walls.
 22. A container as in claim 21, further comprising a groove defined by said upper lips and a rim that extends above said lower lips.
 23. A container as in claim 22, wherein said upper lips reside against said lower lips and said groove is disposed around said rim when said upper portion and lower portion are placed in said closed position.
 24. A container as in claim 16, further comprising arcs formed by said lower walls and said upper walls, said arcs centered on each of said upper and lower walls and said upper and lower walls having a thicker cross-section within at least a portion of said arcs.
 25. A foam container comprising: an upper portion forming a top of a container, said upper portion having a top surface and defining upper walls extending from said top surface; a lower portion forming a base of said container, said lower portion having a bottom surface and defining lower walls extending from said bottom surface; arcs formed by said lower walls and said upper walls, said upper and lower walls having a thicker cross-section within at least a portion of said arcs.
 26. A container as in claim 25, wherein said upper walls comprise four integral walls extending from said top surface and said lower walls comprise four integral walls extending from said bottom surface.
 27. A container as in claim 26, wherein said arcs are centered on each of said walls so that an apex of each arc is proximal to the center of a length of said wall on which said arc is formed.
 28. A container as in claim 25, further comprising a hinge disposed between one of said lower walls and one of said upper walls, said hinge connecting said upper portion and said lower portion together so that said upper portion and lower portion are capable of being placed in a closed position.
 29. A container as in claim 28, further comprising a latch system wherein said upper portion and lower portion are securable together by said latch system.
 30. A container as in claim 29, wherein said latch system is disposed on a side of said upper portion and a side of said lower portion distal to said hinge.
 31. A container as in claim 30, wherein said latch system comprises a latch extending from said upper wall distal from said hinge and a slot defined in said lower wall distal from said hinge, whereby said latch is slidable into said slot to close the container.
 32. A container as in claim 28, further comprising upper lips extending outward from said upper walls and lower lips extending outward from said lower walls.
 33. A container as in claim 32, further comprising a groove defined by said upper lips and a rim that extends above said lower lips.
 34. A container as in claim 33, wherein said upper lips resides against said lower lips and said groove is disposed around said rim when said upper portion and lower portion are placed in said closed position.
 35. A container as in claim 25, wherein said lower walls form a peripheral indented segment therein proximal to said bottom surface.
 36. A container as in claim 35, wherein said upper walls form a peripheral ridge that extends above and around said top surface.
 37. A container as in claim 36, wherein said peripheral indented segment and said peripheral ridge are dimensioned so as to render the container stackable with another container of the same construction. 